On 18/01/2013 shortman wrote:>The BD cams I own are rated 14kns above the .75 size, and some C3's are>10kns.
Of course the rock we place our gear in (esp soft sandstone) isn't always 3 sigma certified and available in pretty colours...

On 18/01/2013 shortman wrote:>The BD cams I own are rated 14kns above the .75 size, and some C3's are 10kns.

I find it interesting that the .3 C4 is rated to 8kN and the #2 C3 is rated to 10kN even though they are similar sizes and cover a very similar range (13.8-23.4mm vs 14.2-22.6mm). The #1 C3 is also rated to 10kN but is smaller still...

On 18/01/2013 ajfclark wrote:>On 18/01/2013 shortman wrote:>>The BD cams I own are rated 14kns above the .75 size, and some C3's are>10kns.>>I find it interesting that the .3 C4 is rated to 8kN and the #2 C3 is>rated to 10kN even though they are similar sizes and cover a very similar>range (13.8-23.4mm vs 14.2-22.6mm). The #1 C3 is also rated to 10kN but>is smaller still...

On 18/01/2013 Jakob wrote:>Hah, thanks for that!>>A bit more math for the masses, a bd cam is rated to 8kn (less for smaller>ones.) 8kn is 800kg, therefore you could actually expect a single cam>to fail under a ff2 fall generating 850kg of force - something which is>not an obvious thing. Common sense would say a 10m fall with 20m rope out>would be worse than a 4m fall with 2m rope out hunting for your first piece,>although in reality you have the system absorbing 2.5x body weight in the>first compared to 10x body weight in second.

Firstly as mentioned by Shorty, all C4s are rated higher than that, and a couple of the C3s, we don't know what cam was in use.

Secondly I wasn't there, but there's no implication that the cam failed at all, just the anchor (which could be cam failure, poor placement or rock failure). The way Jacob's post is written it's implied the cam failed which with the information so far in the thread is speculation.

PS No one's suggesting using a single cam anchor, but making assumptions on failure modes is also unhelpful.

On 18/01/2013 ajfclark wrote:>On 18/01/2013 shortman wrote:>>The BD cams I own are rated 14kns above the .75 size, and some C3's are>10kns.>>I find it interesting that the .3 C4 is rated to 8kN and the #2 C3 is>rated to 10kN even though they are similar sizes and cover a very similar>range (13.8-23.4mm vs 14.2-22.6mm). The #1 C3 is also rated to 10kN but>is smaller still...

Cams can fail. I had a Trango cam rip in half when I came off of the top of Milk Blood. The axle and cam lobes stayed in the placement, the cable ripped out of its little housing. It was only a short fall, as my feet were only at or about the piece.

On close inspection, the thing was just poorly made, so I never used the other two I had ever again, and never bought another piece of gear from Trango.

If the cam in question did fail, then there would be evidence of this in the form of a broken piece of gear. If it ripped from its placement, then that's not gear failure, that's a placement failure.

On 18/01/2013 Eduardo Slabofvic. wrote:>Cams can fail. I had a Trango cam rip in half when I came off of the top>of Milk Blood. The axle and cam lobes stayed in the placement, the cable>ripped out of its little housing. It was only a short fall, as my feet>were only at or about the piece.>
Eduardo, we've been through this. If you place a cam so that it is trapped off-axis, the breaking strength is reduced to a ridiculously low value. There's a good chance that you broke a perfectly functioning cam through user error.

This is an often overlooked advantage which nuts and hexes have; as long as the head stays in the rock, you can pull the cable any direction you like without seriously affecting the strength.

On 18/01/2013 Eduardo Slabofvic. wrote:>On close inspection, the thing was just poorly made, so I never used the other two I had ever again, and never bought another piece of gear from Trango.

I have had Trango gear save me...

On 18/01/2013 One Day Hero wrote:>If you place a cam so that it is trapped off-axis, the breaking strength is reduced to a ridiculously low value.>There's a good chance that you broke a perfectly functioning cam through user error. >>This is an often overlooked advantage which nuts and hexes have; as long>as the head stays in the rock, you can pull the cable any direction you>like without seriously affecting the strength.

True, though poor placements can sometimes be an only option, in which case you either run it out, take the time to build a matrix if possible (preferably using passive gear?), or back off.

Of course the best option is not to fall, ... but then we would have nothing to speculate discuss. Heh, heh, eh huh?

On 18/01/2013 pecheur wrote:>On 18/01/2013 Jakob wrote:>>Hah, thanks for that!>>>>A bit more math for the masses, a bd cam is rated to 8kn (less for smaller>>ones.) 8kn is 800kg, therefore you could actually expect a single cam>>to fail under a ff2 fall generating 850kg of force - something which>is>>not an obvious thing. Common sense would say a 10m fall with 20m rope>out>>would be worse than a 4m fall with 2m rope out hunting for your first>piece,>>although in reality you have the system absorbing 2.5x body weight in>the>>first compared to 10x body weight in second. >>Firstly as mentioned by Shorty, all C4s are rated higher than that, and>a couple of the C3s, we don't know what cam was in use.>>Secondly I wasn't there, but there's no implication that the cam failed>at all, just the anchor (which could be cam failure, poor placement or>rock failure). The way Jacob's post is written it's implied the cam failed>which with the information so far in the thread is speculation.>
Which isn't the way I read it. To me, Jakob is just saying that a FF2 will generate forces which are likely to start breaking things.

No, it was actually a question, that's why I put a question mark after it........but you know, doesn't seem like it would have been a problem anyway if you had been able to climb better and avoided falling off that cruisy soft-touch route.

This is really useful info re: fall factors and the forces created. Thanks for posting that.

I recall early in my climbing career (and I'm still a total bumbly), reading a tragic story about anchor failure in Tahquiz. It didn't end well for the parties involved. It was unclear as to the reasons for the anchor failure (ie poor placement), but according to the recount of the story, the three point anchor was found at the base of the climb, still attached to the belayer. It terrified me that such an event could even happen. I guess that was a healthy response & it saved my ass later!

So, what are thoughts on best practice for setting up belays on multi-pitch routes? Do folks re-set belays depending on the direction of the next pitch? Use the belay as the first piece?

Someone once told me to place gear early and often when starting off on a climb esp where a ff2 was possible. I always clip a piece on the belay as my first piece too (assuming its well placed & well positioned for the climb). What are other ways to minimise the risk?

On 18/01/2013 Team t-rex wrote:>So, what are thoughts on best practice for setting up belays on multi-pitch>routes? Do folks re-set belays depending on the direction of the next pitch?>Use the belay as the first piece? >
To be efficient and safe, set the belay once and make it multi-directional. There's the odd exception where a pitch ends on one end of a big ledge and the other pitch is at the other end but even then it can be faster to belay a ledge-walk like a pitch than treat it as a walk. It doesn't really matter whether you're alternating leads or doing blocks, set each belay right the first time.

>Someone once told me to place gear early and often when starting off on>a climb esp where a ff2 was possible. I always clip a piece on the belay>as my first piece too (assuming its well placed & well positioned for the>climb). What are other ways to minimise the risk?

Anything clipped above the belay is good (the belay is multi-directional isn't it?). Clipping the belay and having the belayer hanging below it can work but watch out for the risk of hitting your belayer - they can come off badly if hit by a falling leader.
If in doubt, abseiling off can often reduce the risk. The climb will still be there another day.